Olinsky is shocked when a criminal from his past returns after six years.
The man is Dennis Lee, a human trafficker who killed several teenagers.
Olinsky struggles to keep it together as he races to catch the villain once and for all.
Roman finds himself in hot water when he hits someone and must rely on Burgess and Voight to get him off the hook when he is suspended. Burgess pursues the officer, but he says that if Roman pays hime $3000, he will drop all of the charges.
The team are on a wild goose chase for Dennis Lee, but when Olinsky comes face to face with him, it's obvious he is debating whether to shoot him between the eyes.
Nadia passes the examination with 95 percent, but worries about what she will do in order to pass the psych test because of her past.
Platt helps her out and she passes, but her next hurdle is the physical test.
Olinsky's wife is hesitant about him taking on the case because of the way he went many years ago and she thinks it is history repeating.
Mouse helps locate everyone involved and Voight makes sure that Dennis and Anna go down for a long time.